1014 SUMMARY OF CURKENT EESfiARCHES KELATINQ TO 



Fresh-water Sponge from Mexico.* — Mr. E. Potts describes 

 Meyenia mexicana n. sp. collected by Prof. E. D. Cope in Lake 

 Xochimilco, about seventeen miles south of the City of Mexico. It 

 differs from the familiar M. fluviatilis chiefly in the far greater length 

 of the shafts of the birotulate spicules. It is further interesting as 

 being only the second species of fresh-water sponge to reach the hand 

 of specialists from that region of N. America. 



Australian Sponges.f — Dr. E. von Lendenfeld's third part of 

 his monograph contains a preliminary description and classification 

 of the Calcispongise ; he accepts with some modifications Polejaeff's 

 sub-orders Homocoela and Heterocoela, which depend on the facts that 

 the endoderm in the one is, and in the other is not, differentiated 

 histologically. Grantessa is a new genus of Uteinse, and a new sub- 

 family Vosmaerinae is instituted for the new genus Vosmaeria, which, 

 with the appearance of a Syconid, does not form colonies ; the new 

 genus Polejna appears as the type of the Polejnae. Various new species 

 are described, and some of what others have regarded as varieties are 

 elevated to species. 



In his fourth part | the author deals with the Myxospongise, which 

 he divides into the Myxinge (identical with the HalisarcinaB of O. 

 Schmidt) and the Gumminse, in which the Chondrosidse are alone 

 found. The structure of Bajulus (B. laxus) n. gen. is fully described, 

 and there are descriptions of Chondrosia ramsayi and three new species 

 of Chondrilla. 



Protozoa. 



Experiments on Formation of Pseiidopodia.§ — Dr. O. Zacharias 

 reports a number of interesting results obtained by modifying the 

 environment of certain cells. 



a. The cylindrical spermatozoa of Polyphemus pediculus, subjected 

 to a 5 per cent, solution of sodie phosphate in distilled water, lengthen 

 out, acquire pseudopodia at both ends, slowly contract again with 

 vigorous motion of the pseudopodia, become spherical and clad with 

 vibratile processes only describable as cilia. There was thus a 

 passage from a more or less quiescent to a pseudopodia and thence to 

 a ciliated phase, and Zacharias notes its interest as showing how 

 little essential difference there is between pseudopodia and cilia. 



h. The amoeboid cells of the intestinal epithelium of Stenostomum 

 leucops, which have a spherical form and are provided with a bunch 

 of long cilia, were similarly treated with the result that they became 

 like flagellate infusorians, each with a long, thick, rapidly moving 

 process, beside which two or three cilia were sometimes seen beating 

 at the original much slower rate. In some Flagellata a similar 

 formation of pseudopodia sometimes occurs, as in Ctrcomonas ramulosa 

 St., and (c) the intermediate form Hsematococcus pluvialis Fltw assumes 



* Amer. Natural., xix. (1885) pp. 810-11. 



t Proc. Linn. Soc. N. S. Wales, ix. (1885) pp. 1083-1150 (9 pis.). 



X Ibid., X. (1885) pp. 3-22 (5 pis.). 



§ Biol. Centralbl., v. (1885) pp. 259-62. 



